Implantable medical devices for treating irregular contractions of the heart with electrical stimuli are well known. Exemplary implantable devices are defibrillators and pacemakers. Various types of electrical leads for defibrillators and pacemakers have been suggested, many of which are placed transvenously. Such leads are introduced into the patient's vasculature at a venous access site and travel through veins to the sites where the leads' electrodes will be implanted or otherwise contact target coronary tissue. Electrodes for transvenously-placed leads can be implanted in the endocardium (the tissue lining the inside of the heart) of the right atrium or ventricle, or alternatively, in the branch vessels of the coronary venous system. In particular, lead electrodes can be implanted in the coronary sinus or a branch vessel thereof for sensing and/or stimulation of the left side of the heart (i.e., the left ventricle).
One difficulty with implanting leads in or about the heart is that the lead may become dislodged from its desired location during or after lead implantation. For example, the lead may become dislodged or otherwise repositioned when a clinician withdraws the guiding catheter used to initially implant the lead. Cardiac leads may also become dislodged by normal physiological activity. In an attempt to prevent cardiac leads from being dislodged, a variety of screws, anchors and other devices have been used to affix cardiac leads at a desired location at or near a patient's heart. Some of these devices, however, do not adequately affix the lead at the desired location. Other devices require a clinician to carry out complex, time-consuming steps during or after lead implantation to properly affix the lead at the desired location.
Thus, there is a need in the art for a device and method for fixating cardiac leads within the coronary vasculature which does not interfere with delivery of the lead and which can be deployed after delivery to provide acute and/or chronic fixation.